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Message-ID: <CAN+gG=H_Qi=WGV8BZ_zavJu3O0+Yj4YcSvjoToHnLop4jueuPw@mail.gmail.com>
Date:	Mon, 26 Nov 2012 09:37:43 +0100
From:	Benjamin Tissoires <benjamin.tissoires@...il.com>
To:	Benjamin Tissoires <benjamin.tissoires@...il.com>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Henrik Rydberg <rydberg@...omail.se>,
	Jiri Kosina <jkosina@...e.cz>,
	Stephane Chatty <chatty@...c.fr>, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 08/11] HID: hid-multitouch: add support for Nexio 42" panel

On Fri, Nov 23, 2012 at 4:31 PM, Benjamin Tissoires
<benjamin.tissoires@...il.com> wrote:
> This device is the worst device I saw. It keeps TipSwitch and InRange
> at 1 for fingers that are not touching the panel.
> The solution is to rely on the field ContactCount, which is accurate
> as the correct information are packed at the begining of the frame.
>
> Unfortunately, CountactCount is most of the time at the end of the report.
> The solution is to pick it when we have the whole report in raw_event.
>
> Fortunately, it occurs that this behavior is pretty well compliant
> with all the devices I saw so far. We can make this class the default then.
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...il.com>
> ---
>  drivers/hid/hid-ids.h        |  3 ++
>  drivers/hid/hid-multitouch.c | 82 ++++++++++++++++++++++++++++++++++++++++----
>  2 files changed, 78 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
> index b84790a..9dfc465 100644
> --- a/drivers/hid/hid-ids.h
> +++ b/drivers/hid/hid-ids.h
> @@ -599,6 +599,9 @@
>  #define USB_VENDOR_ID_NEC              0x073e
>  #define USB_DEVICE_ID_NEC_USB_GAME_PAD 0x0301
>
> +#define USB_VENDOR_ID_NEXIO            0x1870
> +#define USB_DEVICE_ID_NEXIO_MULTITOUCH_420     0x0100

Oops, I made a typo here. The PID should be 0x010d.

I can send a v2 if needed.

Cheers,
Benjamin

> +
>  #define USB_VENDOR_ID_NEXTWINDOW       0x1926
>  #define USB_DEVICE_ID_NEXTWINDOW_TOUCHSCREEN   0x0003
>
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index 50fb79f..36cf346 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -33,6 +33,8 @@
>  #include <linux/usb.h>
>  #include <linux/input/mt.h>
>  #include <linux/string.h>
> +#include <asm/unaligned.h>
> +#include <asm/byteorder.h>
>  #include "usbhid/usbhid.h"
>
>
> @@ -55,6 +57,7 @@ MODULE_LICENSE("GPL");
>  #define MT_QUIRK_NO_AREA               (1 << 9)
>  #define MT_QUIRK_IGNORE_DUPLICATES     (1 << 10)
>  #define MT_QUIRK_HOVERING              (1 << 11)
> +#define MT_QUIRK_CONTACT_COUNT_ACCURATE        (1 << 12)
>
>  struct mt_slot {
>         __s32 x, y, cx, cy, p, w, h;
> @@ -84,6 +87,8 @@ struct mt_device {
>         struct mt_class mtclass;        /* our mt device class */
>         struct mt_fields *fields;       /* temporary placeholder for storing the
>                                            multitouch fields */
> +       struct hid_field *contactcount; /* the hid_field contact count that
> +                                          will be picked in mt_raw_event */
>         unsigned last_field_index;      /* last field index of the report */
>         unsigned last_pen_field_index;  /* last field index of the pen report */
>         unsigned last_slot_field;       /* the last field of a slot */
> @@ -148,7 +153,9 @@ static int cypress_compute_slot(struct mt_device *td)
>  }
>
>  static struct mt_class mt_classes[] = {
> -       { .name = MT_CLS_DEFAULT},
> +       { .name = MT_CLS_DEFAULT,
> +               .quirks = MT_QUIRK_ALWAYS_VALID |
> +                       MT_QUIRK_CONTACT_COUNT_ACCURATE },
>         { .name = MT_CLS_NSMU,
>                 .quirks = MT_QUIRK_NOT_SEEN_MEANS_UP },
>         { .name = MT_CLS_SERIAL,
> @@ -487,6 +494,7 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
>                         td->last_field_index = field->index;
>                         return 1;
>                 case HID_DG_CONTACTCOUNT:
> +                       td->contactcount = field;
>                         td->last_field_index = field->index;
>                         return 1;
>                 case HID_DG_CONTACTMAX:
> @@ -554,6 +562,10 @@ static int mt_compute_slot(struct mt_device *td, struct input_dev *input)
>   */
>  static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
>  {
> +       if ((td->mtclass.quirks & MT_QUIRK_CONTACT_COUNT_ACCURATE) &&
> +           td->num_received >= td->num_expected)
> +               return;
> +
>         if (td->curvalid || (td->mtclass.quirks & MT_QUIRK_ALWAYS_VALID)) {
>                 int slotnum = mt_compute_slot(td, input);
>                 struct mt_slot *s = &td->curdata;
> @@ -665,12 +677,6 @@ static int mt_event(struct hid_device *hid, struct hid_field *field,
>                         td->curdata.h = value;
>                         break;
>                 case HID_DG_CONTACTCOUNT:
> -                       /*
> -                        * Includes multi-packet support where subsequent
> -                        * packets are sent with zero contactcount.
> -                        */
> -                       if (value)
> -                               td->num_expected = value;
>                         break;
>                 case HID_DG_TOUCH:
>                         /* do nothing */
> @@ -700,6 +706,62 @@ static int mt_event(struct hid_device *hid, struct hid_field *field,
>         return 1;
>  }
>
> +/*
> + * Extract/implement a data field from/to a little endian report (bit array).
> + * Copied from hid-core.c.
> + *
> + * Code sort-of follows HID spec:
> + *     http://www.usb.org/developers/devclass_docs/HID1_11.pdf
> + *
> + * While the USB HID spec allows unlimited length bit fields in "report
> + * descriptors", most devices never use more than 16 bits.
> + * One model of UPS is claimed to report "LINEV" as a 32-bit field.
> + * Search linux-kernel and linux-usb-devel archives for "hid-core extract".
> + */
> +
> +static __u32 extract(const struct hid_device *hid, __u8 *report,
> +                    unsigned offset, unsigned n)
> +{
> +       u64 x;
> +
> +       if (n > 32)
> +               hid_warn(hid, "extract() called with n (%d) > 32! (%s)\n",
> +                        n, current->comm);
> +
> +       report += offset >> 3;  /* adjust byte index */
> +       offset &= 7;            /* now only need bit offset into one byte */
> +       x = get_unaligned_le64(report);
> +       x = (x >> offset) & ((1ULL << n) - 1);  /* extract bit field */
> +       return (u32) x;
> +}
> +
> +
> +static int mt_raw_event(struct hid_device *hid, struct hid_report *report,
> +                       u8 *data, int size)
> +{
> +       struct mt_device *td = hid_get_drvdata(hid);
> +       struct hid_field *field = td->contactcount;
> +       unsigned value;
> +
> +       if (field && report->id == field->report->id) {
> +               /*
> +                * Pick in advance the field HID_DG_CONTACTCOUNT as it is
> +                * often placed at the end of the report.
> +                */
> +               if (report->id)
> +                       data++;
> +               value = extract(hid, data, field->report_offset,
> +                               field->report_size);
> +               /*
> +                * Includes multi-packet support where subsequent
> +                * packets are sent with zero contactcount.
> +                */
> +               if (value)
> +                       td->num_expected = value;
> +       }
> +       return 0;
> +}
> +
>  static void mt_set_input_mode(struct hid_device *hdev)
>  {
>         struct mt_device *td = hid_get_drvdata(hdev);
> @@ -1110,6 +1172,11 @@ static const struct hid_device_id mt_devices[] = {
>                 MT_USB_DEVICE(USB_VENDOR_ID_TURBOX,
>                         USB_DEVICE_ID_TURBOX_TOUCHSCREEN_MOSART) },
>
> +       /* Nexio panels */
> +       { .driver_data = MT_CLS_DEFAULT,
> +               MT_USB_DEVICE(USB_VENDOR_ID_NEXIO,
> +                       USB_DEVICE_ID_NEXIO_MULTITOUCH_420)},
> +
>         /* Panasonic panels */
>         { .driver_data = MT_CLS_PANASONIC,
>                 MT_USB_DEVICE(USB_VENDOR_ID_PANASONIC,
> @@ -1247,6 +1314,7 @@ static struct hid_driver mt_driver = {
>         .feature_mapping = mt_feature_mapping,
>         .usage_table = mt_grabbed_usages,
>         .event = mt_event,
> +       .raw_event = mt_raw_event,
>  #ifdef CONFIG_PM
>         .reset_resume = mt_reset_resume,
>         .resume = mt_resume,
> --
> 1.8.0
>
--
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